Acoustic wave filter with different types of resonators

ABSTRACT

Aspects of this disclosure relate to acoustic wave filters that include different types of acoustic wave resonators for series resonators and shunt resonators. In certain embodiments, an acoustic wave filter includes series temperature compensated surface acoustic wave resonators and shunt bulk acoustic wave resonators. Such an acoustic wave filter can be a band pass filter.

CROSS REFERENCE TO RELATED APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR § 1.57.This application claims the benefit of priority of U.S. ProvisionalPatent Application No. 62/925,606, filed Oct. 24, 2019 and titled“ACOUSTIC WAVE FILTER WITH DIFFERENT TYPES OF RESONATORS,” thedisclosure of which is hereby incorporated by reference in its entiretyherein. This application also claims the benefit of priority of U.S.Provisional Patent Application No. 62/925,632, filed Oct. 24, 2019 andtitled “ACOUSTIC WAVE FILTER WITH DIFFERENT TYPES OF RESONATORS INACOUSTIC FILTER COMPONENT AND/OR MULTIPLEXER,” the disclosure of whichis hereby incorporated by reference in its entirety herein.

The present disclosure relates to U.S. patent application Ser. No.______ [Attorney Docket SKYWRKS.987A2], titled “ACOUSTIC WAVE FILTERWITH DIFFERENT TYPES OF RESONATORS IN ACOUSTIC FILTER COMPONENT AND/ORMULTIPLEXER,” filed on even date herewith, the entire disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND Technical Field

Embodiments of this disclosure relate to acoustic wave filters.

Description of Related Technology

An acoustic wave filter can include a plurality of resonators arrangedto filter a radio frequency signal. Example acoustic wave resonatorsinclude surface acoustic wave (SAW) resonators and bulk acoustic wave(BAW) resonators. A surface acoustic wave resonator can include aninterdigital transductor electrode on a piezoelectric substrate. Thesurface acoustic wave resonator can generate a surface acoustic wave ona surface of the piezoelectric layer on which the interdigitaltransductor electrode is disposed. In BAW resonators, acoustic wavespropagate in a bulk of a piezoelectric layer. Example BAW resonatorsinclude film bulk acoustic wave resonators (FBARs) and solidly mountedresonators (SMRs).

Acoustic wave filters can be implemented in radio frequency electronicsystems. For instance, filters in a radio frequency front end of amobile phone can include acoustic wave filters. An acoustic wave filtercan be a band pass filter. A plurality of acoustic wave filters can bearranged as a multiplexer. For example, three acoustic wave filters canbe arranged as a triplexer. As another example, four acoustic wavefilters can be arranged as a quadplexer.

Acoustic wave filters with low insertion loss are generally desirable.However, meeting insertion loss specifications for an entire passband ofan acoustic wave filter can be challenging.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

The innovations described in the claims each have several aspects, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope of the claims, some prominent features ofthis disclosure will now be briefly described.

One aspect of this disclosure is an acoustic wave filter that includes aplurality of series resonators and a plurality of shunt resonators. Theplurality of series resonators including temperature compensated surfaceacoustic wave resonators. The plurality of shunt resonators includingbulk acoustic wave resonators. The plurality of series resonators andthe plurality of shunt resonators are together arranged to filter aradio frequency signal. The acoustic wave filter is a band pass filter.

The plurality of series resonators and the plurality of shunt resonatorscan be co-packaged. The plurality of series resonators can be on a firstdie and the plurality of shunt resonators can be on a second die. Thesecond die can be stacked with and attached to the first die. Thetemperature compensated surface acoustic wave resonators can includerespective interdigital transducer electrodes on a side of the first diethat is facing a side of the second die on which electrodes ofrespective bulk acoustic wave resonators are located. An inductor can beco-packaged with the plurality of series resonators and the plurality ofshunt resonators. A trap circuit can be co-packaged with the pluralityof series resonators and the plurality of shunt resonators. A phaseshift circuit can be co-packaged with the plurality of series resonatorsand the plurality of shunt resonators.

The plurality of series resonators can include a Lamb wave resonator.The plurality of shunt resonators can include a Lamb wave resonator.

The bulk acoustic wave resonators can include a film bulk acoustic waveresonator.

The plurality of shunt resonators and the plurality of series resonatorscan be arranged in a ladder topology.

The acoustic wave filter can include a multi-mode surface acoustic wavefilter coupled in series with the plurality of series resonators.

The plurality of series resonators can include a series bulk acousticwave resonator, and the temperature compensated surface acoustic waveresonators can be coupled to an input/output port of the acoustic wavefilter by way of the series bulk acoustic wave resonator.

The acoustic wave filter can be arranged to support dual connectivity.The acoustic wave filter can have a pass band that includes twooperating bands. The acoustic wave filter can be a receive filter. Theacoustic wave filter can have a pass band that spans an operating bandof a first radio access technology and an operating band of a secondradio access technology, in which the first radio access technology isdifferent than the second radio access technology. The acoustic wavefilter can have a pass band that spans a Long Term Evolution operatingband and a New Radio operating band.

Another aspect of this disclosure is an acoustic wave filter thatincludes: a plurality of series acoustic wave resonators of a firsttype; and a plurality of shunt acoustic wave resonators of a secondtype, the series acoustic wave resonators of the first type having ahigher quality factor below respective resonant frequencies than seriesacoustic resonators of the second type, the shunt acoustic resonators ofthe second type having a higher quality factor in a frequency rangebetween respective resonant frequencies and respective anti resonantfrequencies than shunt acoustic resonators of the first type, and theplurality of series acoustic wave resonators of the first type and theplurality of shunt acoustic wave resonators of the second type togetherarranged as a band pass filter configured to filter a radio frequencysignal.

The plurality of series acoustic resonators of the first type can betemperature compensated surface acoustic wave resonators. The pluralityof shunt acoustic resonators of the second type can be bulk acousticwave resonators.

The plurality of series resonators of the first type can be on a firstdie and the plurality of shunt resonators of the second type can be on asecond die. Electrodes the plurality of series resonators of the firsttype can be on a side of the first die that is facing a side of thesecond die on which electrodes of the plurality of shunt resonators ofthe second type are located.

The acoustic wave filter can be a receive filter with a pass band thatspans a first operating band and a second operating band. The firstoperating band can be associated with a different radio accesstechnology than the second operating band.

Another aspect of this disclosure is an acoustic wave filter thatincludes a plurality of series resonators including bulk acoustic waveresonators; and a plurality of shunt resonators including temperaturecompensated surface acoustic wave resonators, the plurality of seriesresonators and the plurality of shunt resonators together arranged as aband stop filter to filter a radio frequency signal.

The plurality of series resonators and the plurality of shunt resonatorscan be co-packaged. The plurality of series resonators can be on a firstdie and the plurality of shunt resonators are on a second die. Thesecond die can be stacked with and attached to the first die. Thetemperature compensated surface acoustic wave resonators can includerespective interdigital transducer electrodes on a side of the seconddie that is facing a side of the first die on which electrodes ofrespective bulk acoustic wave resonators are located. An inductor can beco-packaged with the plurality of series resonators and the plurality ofshunt resonators. A phase shift circuit can be co-packaged with theplurality of series resonators and the plurality of shunt resonators.The phase shift circuit can include a plurality of interdigitaltransducer electrodes.

The plurality of series resonators can include a Lamb wave resonator.The plurality of shunt resonators can include a Lamb wave resonator. Thebulk acoustic wave resonators can include a film bulk acoustic waveresonator. The plurality of shunt resonators and the plurality of seriesresonators can be arranged in a ladder topology.

Another aspect of this disclosure is acoustic wave filter that includes:a plurality of series acoustic wave resonators of a first type; and aplurality of shunt acoustic wave resonators of a second type, the seriesacoustic wave resonators of the first type having a lower resonantfrequency than the respective shunt acoustic wave resonators of thesecond type, the series acoustic resonators of the first type having ananti-resonant frequency that aligns with the resonant frequency ofrespective shunt acoustic resonators of the second type, and theplurality of series acoustic wave resonators of the second type and theplurality of shunt acoustic wave resonators of the first type togetherarranged as a band stop filter to filter a radio frequency signal.

Another aspect of this disclosure can include an acoustic wave filter inaccordance with any suitable principles and advantages disclosed hereinand a radio frequency circuit element coupled to the acoustic wavefilter. The acoustic wave filter and the radio frequency circuit elementare enclosed within a common module package.

The radio frequency circuit element can be a radio frequency amplifierarranged to amplify a radio frequency signal. The radio frequencycircuit element can be a switch configured to selectively couple theacoustic wave filter to an antenna port of the radio frequency module.

Another aspect of this disclosure is a wireless communication devicethat includes an acoustic wave filter in accordance with any suitableprinciples and advantages disclosed herein, an antenna operativelycoupled to the acoustic wave filter, a radio frequency amplifieroperatively coupled to the acoustic wave filter and configured toamplify a radio frequency signal, and a transceiver in communicationwith the radio frequency amplifier.

The wireless communication device can include a baseband processor incommunication with the transceiver.

The wireless communication device can be configured to support dualconnectivity. The radio frequency amplifier can be a low noiseamplifier, the acoustic wave filter can be a receive filter having apassband that spans a first operating band and a second operating band,and the first operating band can be associated with a different radioaccess technology than the second operating band.

Another aspect of this disclosure is a method of filtering a radiofrequency signal that includes receiving a radio frequency signal at aport of the acoustic wave filter in accordance with any suitableprinciples and advantages disclosed herein and filtering the radiofrequency signal with the acoustic wave filter.

Another aspect of this disclosure is an acoustic filter component thatincludes a first die and a second die. The first die includes aplurality of surface acoustic wave resonators. The first die includes aside on which an interdigital transducer electrode of a first surfaceacoustic wave resonator of the surface acoustic wave resonators ispositioned. The second die includes a plurality of bulk acoustic waveresonators. The second die includes a side on which an electrode of afirst bulk acoustic wave resonator of the bulk acoustic wave resonatorsis positioned. The side of the second die faces the side of the firstdie. The first die is stacked with and attached to the second die. Thesurface acoustic wave resonators are as series resonators of an acousticwave filter. The bulk acoustic wave resonators are as shunt resonatorsof the acoustic wave filter.

The acoustic filter component can include sidewalls positioned betweenthe first die and the second die. The sidewalls can be included in apackaging structure that encloses the surface acoustic wave resonatorsand the bulk acoustic wave resonators in a sealed volume. The first diecan be attached to the second die via the sidewalls.

The acoustic filter component can include a tuning inductor on the sideof the first die. The acoustic filter component of can include a phaseshift circuit co-packaged with the surface acoustic wave resonators andthe bulk acoustic wave resonators. The acoustic filter component caninclude a passive impedance element co-packaged with the surfaceacoustic wave resonators and the bulk acoustic wave resonators. Thepassive impedance element can be included in a tuning network coupled tothe acoustic wave filter.

The surface acoustic wave resonators can be temperature compensatedsurface acoustic wave resonators.

The first die can include a second plurality of surface acoustic waveresonators of a second acoustic wave filter, the second die can includea second plurality of bulk acoustic wave resonators of the secondacoustic wave filter, and the acoustic wave filter and the secondacoustic wave filter can be are included in a multiplexer.

The acoustic wave filter can be a band pass filter.

The acoustic wave filter can be a receive filter having a pass band thatspans a first operating band and a second operating band. The firstoperating band and the second operating band can be associated withdifferent radio access technologies.

Another aspect of this disclosure is an acoustic filter component thatincludes: a first die including a plurality of surface acoustic waveresonators, the first die including a side on which an interdigitaltransducer electrode of a first surface acoustic wave resonator of thesurface acoustic wave resonators is positioned; and a second dieincluding a plurality of bulk acoustic wave resonators, the second dieincluding a side on which an electrode of a first bulk acoustic waveresonator of the bulk acoustic wave resonators is positioned, the sideof the second die facing the side of the first die, the first diestacked with and attached to the second die, surface acoustic waveresonators being arranged as shunt resonators of an acoustic wavefilter, and the bulk acoustic wave resonators being arranged as seriesresonators of the acoustic wave filter.

The acoustic filter component can include sidewalls positioned betweenthe first die and the second die. The sidewalls can be included in apackaging structure that encloses the surface acoustic wave resonatorsand the bulk acoustic wave resonators in a sealed volume. The first diecan be attached to the second die via the sidewalls.

The acoustic filter component can include a passive impedance elementco-packaged with the surface acoustic wave resonators and the bulkacoustic wave resonators. The passive impedance element can be includedin a tuning network coupled to the acoustic wave filter.

The surface acoustic wave resonators can be temperature compensatedsurface acoustic wave resonators.

The acoustic wave filter can be a band stop filter.

Another aspect of this disclosure is a multiplexer that includes a firstfilter and a second filter coupled to the first filter at a common node.The first filter includes a plurality of series temperature compensatedsurface acoustic wave resonators and a plurality of shunt bulk acousticwave resonators together arranged to filter a radio frequency signal.The first filter is a band pass filter.

The series temperature compensated surface acoustic wave resonators canbe on a first die and the shunt bulk acoustic wave resonators can be ona second die. The series temperature compensated surface acoustic waveresonators can include respective interdigital transducer electrodes ona side of the first die that is facing a side of the second die on whichelectrodes of respective shunt bulk acoustic wave resonators arelocated.

The multiplexer can include an inductor that is co-packaged with theseries temperature compensated surface acoustic wave resonators and theshunt bulk acoustic wave resonators. The multiplexer can include a trapcircuit that is co-packaged with the series temperature compensatedsurface acoustic wave resonators and the shunt bulk acoustic waveresonators. The multiplexer can include a phase shift circuit that isco-packaged with the series temperature compensated surface acousticwave resonators and the shunt bulk acoustic wave resonators. The phaseshift circuit can include a plurality of interdigital transducerelectrodes.

The multiplexer can include a third filter coupled to the common node.The first filter can be a receive filter with a first passband thatspans a first receive frequency band and a second receive frequencyband, the second filter can be a first transmit filter with a secondpassband that spans a first transmit band associated with the firstreceive band, and the third filter can be a second transmit filter witha third passband that spans a second transmit band associated with thesecond receive band. The multiplexer can support dual connectivity.

The first filter can have a passband that includes two operating bands.The first filter can have a passband that includes two operating bandsassociated with different radio access technologies. The first filter isarranged can be a receive filter.

The second filter can include series temperature compensated surfaceacoustic wave resonators and shunt temperature compensated surfaceacoustic wave resonators.

The first filter further can include a Lamb wave resonator in serieswith the plurality of the series temperature compensated surfaceacoustic wave resonators. The first filter can include a shunt Lamb waveresonator.

The shunt bulk acoustic wave resonators can include a film bulk acousticwave resonator. The shunt bulk acoustic wave resonators and the seriestemperature compensated surface acoustic wave resonators can be arrangedin a ladder topology. The multiplexer can include a multi-mode surfaceacoustic wave filter coupled in series with the series temperaturecompensated surface acoustic wave resonators.

The first filter can include a series bulk acoustic wave resonator inseries with the series temperature compensated surface acoustic waveresonators. The temperature compensated surface acoustic wave resonatorscan be coupled to an input/output port of acoustic wave filter by way ofthe series bulk acoustic wave resonator.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the innovations have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment. Thus, theinnovations may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this disclosure will now be described, by way ofnon-limiting example, with reference to the accompanying drawings.

FIG. 1A is a cross sectional view of a temperature compensated surfaceacoustic wave (TCSAW) device.

FIG. 1B is a top view of the TCSAW device of FIG. 1A.

FIG. 2 is a cross sectional view of a bulk acoustic wave (BAW) device.

FIG. 3A is a graph that illustrates a resonant frequency (fs) and ananti-resonant frequency (fp) for a shunt TCSAW resonator and a shunt BAWresonator.

FIG. 3B is a graph comparing quality factor of a shunt TCSAW resonatorand a shunt BAW resonator.

FIG. 4A is a graph that illustrates a resonant frequency and ananti-resonant frequency for a series TCSAW resonator and a series BAWresonator.

FIG. 4B is a graph comparing quality factor of a series TCSAW resonatorand a series BAW resonator.

FIG. 5 is a schematic diagram of a ladder filter according to anembodiment.

FIG. 6A is a graph comparing insertion loss of the ladder filter of FIG.5 to an all BAW ladder filter in a passband of the filters.

FIG. 6B is a graph comparing insertion loss of the ladder filter of FIG.5 to an all BAW ladder filter over a wider frequency range than in FIG.6A.

FIG. 7A is a graph comparing insertion loss of the ladder filter of FIG.5 to an all TCSAW ladder filter in a passband of the filters.

FIG. 7B is a graph comparing insertion loss of the ladder filter of FIG.5 to an all TCSAW ladder filter over a wider frequency range than inFIG. 7A.

FIG. 8A is a schematic diagram of a ladder filter according to anotherembodiment.

FIG. 8B is a cross sectional diagram of a Lamb wave resonator.

FIG. 9 is a schematic diagram of a lattice filter.

FIG. 10 is a schematic diagram of a hybrid ladder and lattice filter.

FIG. 11 is a schematic diagram of an acoustic filter that includesladder stages and a multi-mode surface acoustic wave filter.

FIG. 12 is a schematic block diagram of a packaged component thatincludes a plurality of acoustic resonator die.

FIG. 13 is a cross sectional diagram of a co-packaged stacked dieacoustic filter component according to an embodiment.

FIG. 14 is a schematic block diagram of an acoustic filter and a tuningnetwork.

FIGS. 15A, 15B, 15C, and 15D are schematic diagrams of tuning networks.

FIG. 16 is a schematic diagram of a multiplexer with a phase shiftcircuit.

FIG. 17A is a schematic diagram of a multiplexer according to anembodiment.

FIG. 17B is a diagram illustrating the passbands of filters of themultiplexer of FIG. 17A.

FIG. 17C is a diagram of an example dual connectivity network topology.

FIGS. 18A, 18B, 18C, 18D, and 18E are graphs of simulations of themultiplexer of FIG. 17A.

FIG. 19A is a schematic diagram of a duplexer that includes an acousticwave filter according to an embodiment.

FIG. 19B is a schematic diagram of a multiplexer that includes anacoustic wave filter according to an embodiment.

FIG. 20 is a schematic diagram of a radio frequency module that includesan acoustic wave filter according to an embodiment.

FIG. 21 is a schematic block diagram of a module that includes anantenna switch and duplexers according to an embodiment.

FIG. 22 is a schematic block diagram of a module that includes a poweramplifier, a radio frequency switch, and duplexers according to anembodiment.

FIG. 23 is a schematic block diagram of a module that includes a lownoise amplifier, a radio frequency switch, and filters according to anembodiment.

FIG. 24 is a schematic diagram of a radio frequency module that includesan acoustic wave filter according to an embodiment.

FIG. 25A is a schematic block diagram of a wireless communication devicethat includes an acoustic wave filter according to an embodiment.

FIG. 25B is a schematic block diagram of another wireless communicationdevice that includes an acoustic wave filter according to an embodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following description of certain embodiments presents variousdescriptions of specific embodiments. However, the innovations describedherein can be embodied in a multitude of different ways, for example, asdefined and covered by the claims. In this description, reference ismade to the drawings where like reference numerals can indicateidentical or functionally similar elements. It will be understood thatelements illustrated in the figures are not necessarily drawn to scale.Moreover, it will be understood that certain embodiments can includemore elements than illustrated in a drawing and/or a subset of theelements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

Acoustic filters can implement band pass filters. For example, a bandpass filter can be formed from temperature compensated surface acousticwave (TCSAW) resonators. As another example, a band pass filter can beformed from bulk acoustic wave (BAW) resonators, such as film bulkacoustic wave resonators (FBARs).

In acoustic filter applications, insertion loss improvement is typicallydesired by customers. Insertion loss improvement can help a receivechain with achieve a desired noise figure. Insertion loss improvementcan help with implementing a transmit chain with less power consumptionand/or better power handling.

Aspects of this disclosure relate to implementing an acoustic wavefilter from more than one type of acoustic resonator. In certainembodiments, an acoustic wave filter can include series TCSAW resonatorsand shunt BAW resonators. Series TCSAW resonators can achieve higherquality factor (Q) in a frequency range below a resonant frequency (fs),while shunt BAW resonators can achieve a higher Q in a frequency rangebetween fs and an anti-resonant frequency (fp).

Compared to a BAW only acoustic wave filter, an acoustic wave filterwith series TCSAW resonators and shunt BAW resonators can achieve betterlow channel insertion loss. Compared to a TCSAW only acoustic wavefilter, an acoustic wave filter with series TCSAW resonators and shuntBAW resonators can achieve better overall insertion loss. Accordingly,an acoustic wave filter with series TCSAW resonators and shunt BAWresonators can achieve desirable insertion loss.

Example TCSAW resonators and BAW resonators will now be discussed.

FIG. 1A is a cross sectional view of a TCSAW device 10. The TCSAW device10 can be a TCSAW resonator. As illustrated, the TCSAW device 10includes a piezoelectric layer 12, an interdigital transducer (IDT)electrode 14, and a temperature compensation layer 16 over the IDTelectrode 14.

The piezoelectric layer 12 can be a lithium based piezoelectric layer.For example, the piezoelectric layer 12 can be a lithium niobate layer.As another example, the piezoelectric layer 12 can be a lithiumtantalate layer.

In the TCSAW device 10, the IDT electrode 14 is over the piezoelectriclayer 12. As illustrated, the IDT electrode 14 has a first side inphysical contact with the piezoelectric layer 12 and a second side inphysical contact with the temperature compensation layer 16. The IDTelectrode 14 can include aluminum (Al), molybdenum (Mo), tungsten (W),gold (Au), silver (Ag), copper (Cu), platinum (Pt), ruthenium (Ru),titanium (Ti), the like, or any suitable combination or alloy thereof.The IDT electrode 14 can be a multi-layer IDT electrode in someapplications.

In the TCSAW device 10, the temperature compensation layer 16 can bringa temperature coefficient of frequency (TCF) of the TCSAW device 10closer to zero. The temperature compensation layer 16 can have apositive TCF. This can compensate for a negative TCF of thepiezoelectric layer 12. The piezoelectric layer 12 can be lithiumniobate or lithium tantalate, which both have a negative TCF. Thetemperature compensation layer 16 can be a dielectric film. Thetemperature compensation layer 16 can be a silicon dioxide layer. Insome other embodiments, a different temperature compensation layer 16can be implemented. Some examples of other temperature compensationlayers include a tellurium dioxide (TeO₂) layer or a silicon oxyfluoride(SiOF) layer.

FIG. 1B illustrates the IDT electrode 14 of the TCSAW device 10 of FIG.1A in plan view. The view of the TCSAW device 10 in FIG. 1A is along thedashed line from A to A in FIG. 1B. The temperature compensation layer16 is not shown in FIG. 1B to focus on the IDT electrode 14. The IDTelectrode 14 is positioned between a first acoustic reflector 17A and asecond acoustic reflector 17B. The acoustic reflectors 17A and 17B areseparated from the IDT electrode 14 by respective gaps. The IDTelectrode 14 includes a bus bar 18 and IDT fingers 19 extending from thebus bar 18. The IDT fingers 19 have a pitch of λ. The TCSAW device 10can include any suitable number of IDT fingers 19. The pitch λ of theIDT fingers 19 corresponds to a resonant frequency of the TCSAW device10.

FIG. 2 is a cross sectional view of a bulk acoustic wave (BAW) device20. The BAW device 20 can be a BAW resonator. The illustrated BAW device20 is a film bulk acoustic resonator (FBAR). The BAW device 20 includesa first electrode 21, a second electrode 22, a piezoelectric layer 23,an air cavity 24, and a substrate 25. The electrodes 21 and 22 are onopposing sides of the piezoelectric substrate 23. The piezoelectriclayer 23 can be a thin film. The piezoelectric layer 23 can be analuminum nitride layer, for example. In other instances, thepiezoelectric layer 23 can be any other suitable piezoelectric layer.The air cavity 24 is disposed between the electrode 21 and the substrate25. The substrate 25 can be a semiconductor substrate. For example, thesubstrate 25 can be a silicon substrate. The substrate 25 can be anyother suitable substrate, such as a quartz substrate, a sapphiresubstrate, a spinel substrate, a ceramic substrate, a glass substrate,or the like. Although not shown in FIG. 2, the BAW device 20 can includea raised frame structure and/or a recessed frame structure.

FIG. 3A is a graph that illustrates a resonant frequency (fs) and ananti-resonant frequency (fp) for a shunt TCSAW resonator and a shunt BAWresonator. The shunt TCSAW resonator is generally similar to the TCSAWdevice 10 and the shunt BAW resonator is generally similar to the BAWdevice 20. FIG. 3A indicates that the shunt TCSAW resonator and theshunt BAW resonator have similar fs and fp.

FIG. 3B is a graph comparing quality factor of the shunt TCSAW resonatorand the shunt BAW resonator corresponding to the graph of FIG. 3A. FIG.3B indicates that the Q of the shunt TCSAW resonator from fs to fp issignificantly lower than the Q for the shunt BAW resonator from fs tofp. In a ladder filter, such shunt TCSAW resonators can cause more lossat an upper band edge than such shunt BAW resonators.

FIG. 4A is a graph that illustrates fs and fp for a series TCSAWresonator and a series BAW resonator. The series TCSAW resonator isgenerally similar to the TCSAW device 10 and the series BAW resonator isgenerally similar to the BAW device 20. FIG. 4A indicates that theseries TCSAW resonator and the series BAW resonator have similar fs andfp.

FIG. 4B is a graph comparing quality factor of the series TCSAWresonator and the series BAW resonator corresponding to the graph ofFIG. 4A. The Q of the series BAW resonator below fs is degraded relativeto the Q of the TCSAW resonator below fs. In a ladder filter, suchseries BAW resonators can cause more loss at a lower band edge than suchSeries TCSAW resonators.

FIGS. 3A to 4B indicate that TCSAW resonators can result in moreinsertion loss at an upper band edge and that BAW resonators can resultin more insertion loss at a lower band edge than TCSAW resonators for aband pass filter. Achieving low insertion loss at both the lower bandedge and the upper band edge is generally desirable. An acoustic wavefilter with series TCSAW resonators and shunt BAW resonators can achievedesirable insertion loss at both the lower band edge and the upper bandedge of a passband. Similarly, an acoustic wave filter with seriesacoustic wave resonators of a first type and shunt acoustic waveresonators of a second type can also achieve such desirable insertionloss when (a) series resonators of the first type have higher Q thanseries resonators of the second type in a frequency range below fs and(b) shunt resonators of the second type have higher Q than shuntresonators of the first type in a frequency range between fs and fp.These relationships can be for band pass filters.

In certain applications, acoustic resonators can be arranged as a bandstop filter. In such applications, the relationship of the seriesacoustic resonators and shunt acoustic resonators can be reversedrelative to a band pass filter. For example, an acoustic wave filterarranged as a band stop filter with shunt TCSAW resonators and seriesBAW resonators can achieve desirable characteristics in a stop band. Thefp of shunt TCSAW resonators can align to (e.g., be equal to orapproximately equal to) fs of respective series BAW resonators for aband stop filter. The shunt TCSAW resonators can have higher resonantfrequencies than respective series BAW resonators. The followingrelationship can hold for resonators of a band stop filter:fs_BAW<fp_BAW=fs_TCSAW<fp_TCSAW. Other suitable types of acousticresonators with similar characteristics and/or satisfying theserelationships can alternatively or additionally be used in a band passfilter to achieve desirable characteristics in a stop band of the bandstop filter.

FIG. 5 is a schematic diagram of a ladder filter 50 according to anembodiment. The ladder filter 50 includes shunt BAW resonators 52 andseries TCSAW resonators 54 coupled between RF input/output ports Port1and Port2. The ladder filter 50 is an example topology of a band passfilter formed from acoustic resonators. In a band pass filter with aladder filter topology, the shunt resonators can have lower resonantfrequencies than the series resonators. The ladder filter 50 can bearranged to filter an RF signal. As illustrated, the shunt BAWresonators include resonators R1, R3, R5, R7, and R9. The illustratedseries TCSAW resonators 54 include resonators R2, R4, R6, R8, and R10.The first RF input/output port Port1 can be a transmit port for atransmit filter or a receive port for a receive filter. The second RFinput/output port Port2 can be an antenna port. Any suitable number ofseries acoustic resonators can be in included in a ladder filter. Anysuitable number of shunt acoustic wave resonators can be included in aladder filter.

FIG. 6A is a graph comparing insertion loss of the ladder filter of FIG.5 to an all BAW ladder filter in a passband of the filters. The ladderfilter 50 has a lower insertion loss at a lower band edge compared tothe all BAW ladder filter. The low channel insertion loss can improvewith series TCSAW resonators due to Q of the series TCSAW resonatorsbeing higher below fs than for series BAW resonators.

FIG. 6B is a graph comparing insertion loss of the ladder filter 50 ofFIG. 5 to an all BAW ladder filter over a wider frequency range than inFIG. 6A. FIG. 6B indicates that the ladder filter 50 can achieveinsertion loss below a specification outside of the passband.

FIG. 7A is a graph comparing insertion loss of the ladder filter 50 ofFIG. 5 to an all TCSAW ladder filter in a passband of the filters. Theladder filter 50 has a lower insertion loss throughout the passbandcompared to the all TCSAW ladder filter. The insertion loss at an upperband edge is significantly improved for the ladder filter 50 compared tothe all TCSAW ladder filter. The shunt BAW resonators of the ladderfilter 50 can have a higher Q between fs and fp compared to shunt TCSAWresonators of the all TCSAW ladder filter. This higher Q can improve theinsertion loss for the ladder filter 50.

FIG. 7B is a graph comparing insertion loss of the ladder filter 50 ofFIG. 5 to an all TCSAW ladder filter over a wider frequency range thanin FIG. 7A. FIG. 7B indicates that the ladder filter 50 can achieveinsertion loss below a specification outside of the passband.

FIG. 8A is a schematic diagram of a ladder filter 80 according toanother embodiment. The ladder filter 80 includes a plurality ofacoustic resonators R1, R2, . . . , RN-1, and RN arranged between afirst input/output port PORT1 and a second input/output port PORT1. Oneof the input/output ports PORT1 or PORT2 can be an antenna port. Incertain instances, the other of the input/output ports PORT1 or PORT2can be a receive port. In some other instances, the other of theinput/output ports PORT1 or PORT2 can be a transmit port.

The ladder filter 80 illustrates that any suable number of ladder stagescan be implemented in a ladder filter in accordance with any suitableprinciples and advantages disclosed herein. Ladder stages can start witha series resonator or a shunt resonator from any input/output port ofthe ladder filter 80 as suitable. As illustrated, the first ladder stagefrom the input/output port PORT1 begins with a shunt resonator R1. Asalso illustrated, the first ladder stage from the input/output portPORT2 begins with a series resonator RN.

The ladder filter 80 includes shunt resonators R1 and RN-1 and seriesresonator R2 and RN. The series resonators of the ladder filter 80including resonators R2 and RN can be acoustic resonators of a firsttype that have higher Q than series resonators of a second type in afrequency range below fs. The shunt resonators of the ladder filter 80including resonators R1 and RN-1 can be acoustic resonators of thesecond type and have higher Q than shunt resonators of the first type ina frequency range between fs and fp. This can lead to a reducedinsertion loss. The ladder filter 80 can be a band pass filter withseries resonators of the first type and shunt resonators of the secondtype. In some other embodiments, the series resonators of the ladderfilter 80 including resonators R2 and RN can be acoustic resonators ofthe second type and the shunt resonators of the ladder filter 80including resonators R1 and RN-1 can be acoustic resonators of the firsttype. In such embodiments, the ladder filter 80 can be a band passfilter.

The resonators of the first type can be TCSAW resonators and theresonators of the second type can be BAW resonators. Accordingly, theladder filter 80 can include series TCSAW resonators and shunt BAWresonators in certain embodiments. Such BAW resonators can include FBARsand/or solidly mounted resonators (SMRs).

The resonators of the first type can be multi-layer piezoelectricsubstrate (MPS) SAW resonators and the resonators of the second type canbe BAW resonators. Accordingly, the ladder filter 80 can include seriesMPS SAW resonators and shunt BAW resonators. Such BAW resonators caninclude FBARs and/or SMRs in certain embodiments.

The resonators of the first type can be non-temperature compensated SAWresonators and the resonators of the second type can be BAW resonators.Accordingly, the ladder filter 80 can include series non-temperaturecompensated SAW resonators and shunt BAW resonators in certainembodiments. Such BAW resonators can include be FBARs and/or SMRs.

In a band pass filter with a ladder filter topology, such as theacoustic wave filter 80, the shunt resonators can have lower resonantfrequencies than the series resonators. In certain embodiments, theshunt resonators of the acoustic wave filter 80 are BAW resonators andthe series resonators of the acoustic wave filter 80 are TCSAWresonators. In such embodiments, the acoustic wave filter 80 can be aband pass filter. Such a band pass filter can achieve low insertion lossat both a lower band edge and an upper band edge of a passband.

In a band stop filter with a ladder filter topology, such as acousticwave filter 80, the shunt resonators can have higher resonantfrequencies than the series resonators. In certain embodiments, theacoustic wave filter 80 is a band stop filter, the shunt resonators ofthe acoustic wave filter 80 are TCSAW resonators and the seriesresonators of the acoustic wave filter 80 are BAW resonators. Such aband stop filter can achieve desirable characteristics in a stop band ofthe band stop filter.

In some applications of an acoustic wave filter that includes TCSAWseries resonators and BAW shunt resonators, such as a transmit filterwith a relatively high power handling specification, one or more seriesresonators close to a transmit port (or the lower frequency seriesresonators) can be BAW resonators to help with ruggedness.

In certain applications, the ladder filter 80 can be included in amultiplexer in which relatively high gamma for the ladder filter 80 inone or more higher frequency carrier aggregation bands is desired. Insuch applications, an acoustic filter can include shunt resonators ofthe shunt type and an acoustic resonator of the second type can beincluded as a series resonator by which other series resonators of thefirst type are coupled to a common port of the multiplexer. This canincrease gamma of the ladder filter 80 in the one or more higherfrequency carrier aggregation bands. For example, in applications wherethe second input/output port PORT2 is a common port of a multiplexer,the series resonator RN can be a BAW resonator, other series resonatorsof the ladder filter 80 can be TCSAW resonators, and the shuntresonators R1 and RN-1 can be BAW resonators. By having the seriesresonator RN closest to the common node be a BAW resonator instead of aTCSAW resonator, gamma can be increased for the ladder filter 80 in oneor more higher frequency carrier aggregation bands in such applications.

In some applications, the ladder filter 80 can be a transmit filter. Insuch applications, an acoustic resonator of the second type can beincluded as a series resonator by which other series resonators of thefirst type are coupled to a transmit port of the transmit filter. Forexample, in applications where the second input/output port PORT2 is atransmit port of a transmit filter, the series resonator RN can be a BAWresonator, other series resonators of the ladder filter 80 can be TCSAWresonators, and the shunt resonators R1 and RN-1 can be BAW resonators.

In certain applications, the ladder filter 80 can include more than twotypes of acoustic resonators. In such applications, the majority of theseries resonators can be acoustic resonators of the first type (e.g.,TCSAW resonators) and the majority of shunt resonators can be resonatorsof the second type (e.g., BAW resonators). The ladder filter 80 caninclude a third type of resonator as a shunt resonator and/or as aseries resonator in such applications. The third type of resonator canbe a Lamb wave resonator, for example. One such example Lamb waveresonator will be discussed with reference to FIG. 8B. The acoustic wavefilter 80 can include a plurality series resonators includingtemperature compensated surface acoustic wave resonators and a pluralityshunt resonators including a Lamb wave resonator arranged as shuntresonator. The acoustic wave filter 80 can include a plurality seriesresonators including a Lamb wave resonator and a plurality shuntresonators including bulk acoustic wave resonators arranged as shuntresonators.

FIG. 8B is a cross sectional diagram of a Lamb wave resonator 85. A Lambwave resonator can implement one or more series resonators and/or one ormore shunt resonators in the ladder filter 80. The Lamb wave resonator85 includes feature of a SAW resonator and an FBAR. As illustrated, theLamb wave resonator 85 includes a piezoelectric layer 23, an IDTelectrode 14 on the piezoelectric layer 23, and an electrode 21. Theresonant frequency of the Lamb wave resonator 85 can be based on thethickness of the piezoelectric layer 23 and/or the geometry of the IDTelectrode 14. An air cavity 24 is disposed between the electrode 21 anda substrate 25. Although the Lamb wave resonator 85 of FIG. 8A is a freestanding Lamb wave resonator, a solidly mounted resonator (SMR) Lambwave resonator with a solid acoustic mirror (e.g., acoustic Braggreflectors) can alternatively or additionally be implemented.

An acoustic wave filter including more than one type of acousticresonator in accordance with any suitable principles and advantagesdisclosed herein can be implemented in a variety of different filtertopologies. Example filter topologies include without limitation ladderfilters, lattice filters, hybrid ladder and lattice filters, filtersthat include ladder stages and a multi-mode SAW filter, and the like.Some example filter topologies will now be discussed.

FIG. 9 is a schematic diagram of a lattice filter 90. The lattice filter90 is an example topology of a band pass filter formed from acousticwave resonators. The lattice filter 80 can be arranged to filter an RFsignal. As illustrated, the lattice filter 90 includes acoustic waveresonators RL1, RL2, RL3, and RL4. The acoustic wave resonators RL1 andRL2 are series resonators. The acoustic wave resonators RL3 and RL4 areshunt resonators. The illustrated lattice filter 90 has a balanced inputand a balanced output. The lattice filter 90 can be implemented withdifferent type of acoustic resonators in accordance with any suitableprinciples and advantages disclosed herein. For example, the seriesresonators RL1 and RL2 can be TCSAW resonators and the shunt resonatorsRL3 and RL4 can be BAW resonators for a band pass filter.

FIG. 10 is a schematic diagram of a hybrid ladder and lattice filter100. The illustrated hybrid ladder and lattice filter includes seriesacoustic resonators RL1, RL2, RH3, and RH4 and shunt acoustic resonatorsRL3, RL4, RH1, and RH2. The hybrid ladder and lattice filter 100 can beimplemented with different type of acoustic resonators in accordancewith any suitable principles and advantages disclosed herein. Forexample, the series resonators RL1, RL2, RH3, and RH4 can be TCSAWresonators and the shunt resonators RL3, RL4, RH1, and RH2 can be BAWresonators for a band pass filter.

FIG. 11 is a schematic diagram of an acoustic filter 110 that includesladder stages and a multi-mode surface acoustic wave filter 112. Theillustrated acoustic filter 110 includes series resonators R2 and R4,shunt resonators R1 and R3, and multi-mode surface acoustic wave filter112. The filter 110 can be a receive filter. The multi-mode surfaceacoustic wave filter 112 can be connected to a receive port. Themulti-mode surface acoustic wave filter 112 includes longitudinallycoupled IDT electrodes. The multi-mode surface acoustic wave filter 112can include a temperature compensation layer over longitudinally coupledIDT electrodes in certain applications. The series resonators R2 and R4can be TCSAW resonators and the shunt resonators R1 and R3 can be BAWresonators for a band pass filter. The shunt resonators R1 and R3 beingBAW resonators can help with lower skirt steepness and insertion loss.

Acoustic filters disclosed herein include more than one type of acousticwave resonator. Such filters can be implemented on a plurality ofacoustic filter die. The plurality of acoustic filter die can be stackedand co-packaged with each other in certain applications. Embodiments ofpackaged components will now be discussed.

FIG. 12 is a schematic block diagram of a packaged component 120 thatincludes a plurality of acoustic resonator die 122 and 124. The packagedcomponent 120 includes a first acoustic resonator die 122 and a secondacoustic resonator die 124. An acoustic filter can include seriesacoustic resonators of the first acoustic resonator die 122 and shuntacoustic resonators of the second acoustic resonator die 124. In certainapplications, a duplexer or other multiplexer can include seriesacoustic resonators on the first acoustic resonator die 122 and shuntacoustic resonators on the second acoustic resonator die 124. The firstacoustic resonator die 122 can be a TCSAW die. The second acousticresonator die 124 can be a BAW die. The acoustic resonator die 122 and124 can be positioned on a common packaging substrate, such as alaminate substrate. The acoustic resonator die 122 and the acousticresonator die 124 can be stacked with each other in certainapplications.

FIG. 13 is a cross sectional diagram of a co-packaged stacked dieacoustic filter component 130 according to an embodiment. Theco-packaged stacked die acoustic filter component 130 can implement theladder filter 50 of FIG. 5 and/or the ladder filter 80 of FIG. 8A. Theco-packaged stacked die acoustic filter component 130 includes a TCSAWdie stacked with and attached to a BAW die. The BAW die includes a firstsubstrate 131 and a BAW resonator 134 on the first substrate 131. Thefirst substrate 131 can be a silicon substrate, for example. Theillustrated BAW resonator 134 is an FBAR. The illustrated BAW resonator134 includes a raised frame structure. The TCSAW die includes a secondsubstrate 132 and a TCSAW resonator 135 on the second substrate 132. Thesecond substrate 132 can be a lithium niobate substrate or a lithiumtantalate substrate. The BAW resonator 134 can be a shunt resonator ofan acoustic wave filter and the TCSAW resonator 135 can be a seriesresonator of the acoustic wave filter. The BAW resonator 134 can beelectrically connected to the TCSAW resonator 135 within the co-packagedstacked die acoustic filter component 130.

Any suitable number of BAW resonators can be included on the firstsubstrate 131. For example, additional BAW resonators can be on thefirst substrate 131 of the co-packaged stacked die acoustic filtercomponent 130 can be positioned behind and/or in front of the BAWresonator 134. Such BAW resonators can include a plurality of BAWresonators of an acoustic wave filter and/or BAW resonators of two ormore acoustic wave filters.

Any suitable number of TCSAW resonators can be included on the secondsubstrate 132. For example, additional TCSAW resonators can be on thesecond substrate 132 of the co-packaged stacked die acoustic filtercomponent 130 can be positioned behind and/or in front of the TCSAWresonator 135. Such TCSAW resonators can include a plurality of TCSAWresonators of an acoustic wave filter and/or TCSAW resonators of two ormore acoustic wave filters.

A Lamb wave element can be included on the second substrate 132 in someapplications. Such a Lamb wave element can be a resonator of an acousticwave filter that includes the TCSAW resonator 135 or a delay element ina phase shift circuit. A Lamb wave element can be included on the firstsubstrate 131 in some applications. Such a Lamb wave element can be aresonator of an acoustic filter that includes the BAW resonator 134 or adelay element in a phase shift circuit.

Active sides of the substrates 131 and 132 face each other. The BAWresonator 134 includes an electrode on a side of the first substrate 131that faces a side of the second substrate 132 on which the IDT electrodeof the TCSAW resonator 135 is positioned. The BAW resonator 134 and theTCSAW resonator 135 are enclosed by the first substrate 131, the secondsubstrate 132, and sidewalls 133. The BAW resonator 134 and the TCSAWresonator 135 are hermetically sealed together within a cavity. Thesidewalls 133 are included in a packaging structure that encloses theBAW resonator 134 and the TCSAW resonator 135 in a sealed volume. Asillustrated, the TCSAW die and the BAW die are attached via thesidewalls 133.

One or more other components can be enclosed in the co-packaged stackeddie acoustic filter component 130 together with the BAW resonator 134and the TCSAW resonator 135. The one or more other components caninclude passive impedance element(s) of a tuning network, a trapcircuit, phase delay elements, the like, or any suitable combinationthereof. For example, the illustrated co-packaged stacked die acousticfilter component 130 includes tuning network including a tuning inductor136. The tuning network can be a matching network. The tuning inductor136 can be a matching inductor. The tuning network can be coupled to theacoustic wave filter that includes the series TCSAW resonator 135 andthe shunt BAW resonator 134. Example tuning networks will be discussedwith reference to FIGS. 14 to 15D. Alternatively or additionally, aphase shift circuit can be implemented using IDTs on the secondsubstrate 132 to provide cancellation of noise components for theacoustic wave filter. An example of such a phase shift circuit will bediscussed with reference to FIG. 16.

The illustrated co-packaged stacked die acoustic filter component 130also includes vias 137 though the first substrate 131 to provideelectrical connections to contacts 138 of the co-packaged stacked dieacoustic filter component 130.

FIG. 14 is a schematic block diagram of a system 140 that includes anacoustic wave filter 142 and a tuning network 144. The tuning network144 can provide impedance matching, phase rotation, and/or other tuningfor the acoustic wave filter 142. The acoustic wave filter 142 can beimplemented in accordance with any suitable principles and advantagesdisclosed herein. One or more components of the tuning network 144 canbe co-packaged with acoustic resonators of the acoustic wave filter 142.

FIGS. 15A, 15B, 15C, and 15D are schematic diagrams of tuning networks.These tuning networks are inductor-capacitor tuning networks that canimplement the tuning network 144 of FIG. 14. The tuning inductor 136 ofFIG. 13 can implement any of the inductors shown in FIGS. 15A to 15D.FIG. 15A illustrates a tuning network 150 that includes a capacitor C1in parallel with an inductor L1. FIG. 15B illustrates a tuning network152 that includes a capacitor C1 in series with an inductor L2. FIG. 15Cillustrates a tuning network 154 that includes a parallelcapacitor-inductor circuit in series with an inductor L2, in which theparallel capacitor-inductor circuit includes a capacitor C1 in parallelwith an inductor L1. FIG. 15C illustrates a tuning network 156 thatincludes a parallel capacitor-inductor circuit in series with acapacitor C2, in which the parallel capacitor-inductor circuit includesa capacitor C1 in parallel with an inductor L1. Any of the capacitors ofFIGS. 15A to 15D can be implemented by an explicit capacitor and/oracoustic resonator arranged as a capacitor.

FIG. 16 is a schematic diagram of a multiplexer 160 with a phase shiftcircuit 166. As illustrated, the multiplexer 160 includes a first filter162, a second filter 164, and a phase shift circuit 166. The illustratedmultiplexer 160 is a duplexer. The first filter 162 and the secondfilter 164 are coupled together at a common node, which is an antennanode ANT in FIG. 16.

The first filter 162 can be a transmit filter and the second filter 164can be a receive filter. Alternatively, the first filter 162 can be areceive filter and the second filter 164 can be another receive filter.Alternatively, the first filter 162 can be a transmit filter and thesecond filter 164 can be another receive filter.

The first filter 162 can be implemented in accordance with any suitableprinciples and advantages disclosed herein. For example, the firstfilter 162 can include series TCSAW resonators and shunt BAW resonators.The second filter 164 can be an acoustic wave filter, aninductor-capacitor filter, or a hybrid acoustic inductor-capacitorfilter. In certain instances, the first filter 162 and the second filter164 can each be implemented with at least two types of acousticresonators in accordance with any suitable principles and advantagesdisclosed herein.

The phase shift circuit 166 can generate an anti-phase radio frequency(RF) signal to cancel a target signal at a desired frequency. The phaseshift circuit 166 can improve the isolation and attenuation of RFacoustic wave filters, such as BAW filters (e.g., FBAR filters or SMRfilters), SAW filters, and Lamb wave filters in the multiplexer 160. Theillustrated phase shift circuit 166 can provide cancelation and/orisolation between a transmit port and a receive port, between twodifferent transmit ports, or between two different receive ports. Thephase shift circuit 166 can be implemented in a co-packaged stacked dieacoustic filter component. For example, the phase shift circuit 166 caninclude IDTs on the same piezoelectric substrate as TCSAW resonators ofthe first filter 162 in a co-packaged stacked die acoustic filtercomponent. The phase shift circuit 166 can be implemented in accordancewith any suitable principles and advantages described in U.S. Pat. No.9,246,533 and/or U.S. Pat. No. 9,520,857, the disclosures of each ofthese patents are hereby incorporated by reference in their entiretiesherein.

FIG. 17A is a schematic diagram of a multiplexer 170 according to anembodiment. The multiplexer 170 can support dual connectivity. In dualconnectivity, such as E-UTRAN New Radio-Dual Connectivity (EN-DC),fourth generation (4G) Long Term Evolution (LTE) signals and fifthgeneration (5G) New Radio (NR) signals can be separately received in auser equipment and the streams can be aggregated. With dualconnectivity, the 4G and 5G signals can be received concurrently.

The illustrated multiplexer 170 is a triplexer. As illustrated, themultiplexer 170 includes a first transmit filter 172 coupled between afirst transmit node B_(A) Tx and a common node ANT, a second transmitfilter 174 coupled between a second transmit node B_(B) Tx and thecommon node ANT, and a receive filter 176 coupled between a receive nodeB_(A)+B_(B) Rx and the common node ANT. The triplexer 170 also include afirst series inductor LS1 in series between the first transmit nodeB_(A) Tx and the first transmit filter 172, a second series inductor LS2in series between the second transmit node B_(B) Tx and the secondtransmit filter 174, a third series inductor LS3 in series between thereceive node B_(A)+B_(B) Rx and the receive filter 176, and a shuntinductor LA1 coupled to the common node ANT. In FIG. 17A, the firsttransmit filter 172, the second transmit filter 174, and the receivefilter 176 are coupled to each other at the common node ANT. The commonnode ANT can be an antenna node.

FIG. 17B is a diagram illustrating the passbands of filters 172, 174,and 176 of the multiplexer 170 of FIG. 17A. The filters 172, 174, and176 of the multiplexer 170 can each be band pass filters. The firsttransmit filter 172 can have passband that includes a Band A transmitband. The second transmit filter 172 can have a passband that includes aBand B transmit band. The receive filter 176 can have a passband thatincludes both a Band A receive band and a Band B receive band. This canenable the receive filter 176 to concurrently receive and filter Band Aand Band B receive signals. The Band A receive band can overlap with theBand B receive band in certain applications. The Band A receive band canbe non-overlapping with the Band B receive band in some otherapplications. Band A and Band B can be associated with different radioaccess technologies. For example, Band A can be a 4G LTE band and Band Bcan be a 4G NR band.

As shown in FIG. 17B, passband of the receive filter 176 can have alower edge that is above the passband of the first transmit filter 172and an upper edge that is below the passband of the second transmitfilter 174. The lower edge of the passband of the receive filter 176 canbe relatively close to an upper edge of the passband of the firsttransmit filter 172. The upper edge of the passband of the receivefilter 176 can be relatively close to a lower edge the passband of thesecond transmit filter 172.

The receive filter 176 can support a relatively wide passband and/orrelatively narrow separation. The relatively wide passband can span atleast two receive operating bands. The relatively narrow separation candue to a relatively narrow gap in between the respective transmit andreceive operating bands. As one example, the gap between a transmit bandand corresponding receive band can be less than 2% (e.g., between 0.5%and 2%) of a frequency halfway between the transmit band and the receiveband.

A relatively large coupling factor and a relatively high Q at resonancecan be desirable for the receive filter 176. This can contribute to thereceive filter 176 achieving a relatively low insertion loss over arelatively wide passband. In the multiplexer 170, the receive filter 176can include two types of acoustic resonators in accordance with anysuitable principles and advantages disclosed herein. For example, thereceive filter 176 can include a plurality of series temperaturecompensated surface acoustic wave resonators and a plurality of shuntbulk acoustic wave resonators together arranged to filter a radiofrequency signal. The transmit filters 172 and/or 174 can include anysuitable filters, such as one or more acoustic wave filters, one or moreacoustic wave filters that include two or more types of acoustic waveresonators (e.g., one or more filters with series TCSAW resonators andshunt BAW resonators), one or more inductor-capacitor filters, or one ormore hybrid filters that includes an inductor-capacitor filter andacoustic resonators. As one example, the transmit filters 172 and 174can each be TCSAW filters.

Filters, such as the filter 176 of FIG. 17B, that include a pass bandthat spans operating bands for two different radio access technologiescan be implemented in dual connectivity applications. An example dualconnectivity network topology will be discussed with reference to FIG.17C.

With the introduction of the 5G NR air interface standards, the 3rdGeneration Partnership Project (3GPP) has allowed for the simultaneousoperation of 5G and 4G standards in order to facilitate the transition.This mode can be referred to as Non-Stand-Alone (NSA) operation orE-UTRAN New Radio-Dual Connectivity (EN-DC) and can involve both 4G and5G carriers being simultaneously transmitted from a user equipment (UE).EN-DC can present technical challenges for measuring power associatedwith individual transmit paths. Radio frequency systems disclosed hereincan measure power associated with a transmit path in dual connectivityapplications.

In certain EN-DC applications, dual connectivity NSA involves overlaying5G systems onto an existing 4G core network. For dual connectivity insuch applications, the control and synchronization between the basestation and the UE can be performed by the 4G network while the 5Gnetwork is a complementary radio access network tethered to the 4Ganchor. The 4G anchor can connect to the existing 4G network with theoverlay of 5G data/control.

FIG. 17C is a diagram of an example dual connectivity network topology.This architecture can leverage LTE legacy coverage to ensure continuityof service delivery and the progressive rollout of 5G cells. A UE 180can simultaneously receive dual downlink LTE and NR carriers. The UE 180can receive a downlink LTE carrier Rx1 from an Evolved Node B (eNB) 181while receiving a downlink NR carrier Rx2 from the gNode B (gNB) 182 toimplement dual connectivity. Any suitable combination of uplink carriersTx1, Tx2 and/or downlink carriers Rx1, Rx2 can be concurrentlytransmitted via wireless links in the example network topology of FIG.17C. The eNB 181 can provide a connection with a core network, such asan Evolved Packet Core (EPC). The gNB 182 can communicate with the corenetwork via the eNB 181. Control plane data can be wirelesslycommunicated between the UE 180 and eNB 181. The eNB 181 can alsocommunicate control plane data with the gNB 182.

In the example dual connectivity topology of FIG. 17C, any suitablecombinations of standardized bands and radio access technologies (e.g.,FDD, TDD, SUL, SDL) can be wirelessly transmitted and received. This canpresent technical challenges related to having multiple separate radiosand bands functioning in the UE 180. With a TDD LTE anchor point,network operation may be synchronous, in which case the operating modescan be constrained to Tx1/Tx2 and Rx1/Rx2, or asynchronous which caninvolve Tx1/Tx2, Tx1/Rx2, Rx1/Tx2, or Rx1/Rx2. When the LTE anchor is afrequency division duplex (FDD) carrier, the TDD/FDD inter-bandoperation can involve simultaneous Tx1/Rx1/Tx2 and Tx1/Rx1/Rx2.

FIGS. 18A, 18B, 18C, 18D, and 18E are graphs of simulations of themultiplexer 170 of FIG. 17A. FIG. 18A is a graph that includes a curvefor a passband for the first transmit filter 172 with the scale on theright side in decibels (dB) and noise in the passband with the scale onthe left side in dB. FIG. 18B is a graph that includes a curve for apassband for the receive filter 176 with the scale on the right side indecibels and noise in the passband with the scale on the left side indB. FIG. 18C is a graph that includes a curve for a passband for thesecond transmit filter 174 with the scale on the right side in dB andnoise in the passband with the scale on the left side in dB.

FIG. 18D zooms in on insertion loss for the receive passband from thegraph of FIG. 18B. FIG. 18D is a graph of the passband for the receivefilter 176 of the 176 with curves for (a) series TCSAW resonators andshunt BAW resonators, (b) all TCSAW resonators, and (c) all BAWresonators. FIG. 18E is similar to the graph of FIG. 18D but assumesperfect matching. These graphs indicate that that the receive filter 176having series TCSAW resonators and shunt BAW resonators can improveinsertion loss in the passband of the receive filter 176 by 0.3 dB to0.5 dB relative to the other receive filters simulated.

FIG. 19A is a schematic diagram of a duplexer 190 that includes anacoustic wave filter according to an embodiment. The duplexer 190includes a first filter 192 and a second filter 194 coupled to togetherat a common node COM. One of the filters of the duplexer 190 can be atransmit filter and the other of the filters of the duplexer 190 can bea receive filter. The transmit filter and/or the receive filter can berespective ladder filters with acoustic wave resonators having atopology similar to the ladder filter 50 of FIG. 5 and the ladder filter80 of FIG. 8A. In some other instances, such as in a diversity receiveapplication, the duplexer 190 can include two receive filters. Thecommon node COM can be an antenna node.

The first filter 192 is an acoustic wave filter arranged to filter aradio frequency signal. The first filter 192 can include acoustic waveresonators coupled between a first radio frequency node RF1 and thecommon node. The first radio frequency node RF1 can be a transmit nodeor a receive node. The first filter 192 includes two types of acousticresonators in accordance with any suitable principles and advantagesdisclosed herein.

The second filter 194 can be any suitable filter arranged to filter asecond radio frequency signal. The second filter 194 can be, forexample, an acoustic wave filter, an acoustic wave filter that includestwo types of acoustic resonators, an LC filter, a hybrid acoustic waveLC filter, or the like. The second filter 194 is coupled between asecond radio frequency node RF2 and the common node. The second radiofrequency node RF2 can be a transmit node or a receive node

Although example embodiments may be discussed with filters or duplexersfor illustrative purposes, any suitable the principles and advantagesdisclosed herein can be implemented in a multiplexer that includes aplurality of filters coupled together at a common node. Examples ofmultiplexers include but are not limited to a duplexer with two filterscoupled together at a common node, a triplexer with three filterscoupled together at a common node, a quadplexer with four filterscoupled together at a common node, a hexaplexer with six filters coupledtogether at a common node, an octoplexer with eight filters coupledtogether at a common node, or the like. One or more filters of amultiplexer can include an acoustic wave filter including two types ofacoustic resonators in accordance with any suitable principles andadvantages disclosed herein.

FIG. 19B is a schematic diagram of a multiplexer 195 that includes anacoustic wave filter according to an embodiment. The multiplexer 195includes a plurality of filters 192 to 196 coupled together at a commonnode COM. The plurality of filters can include any suitable number offilters including, for example, 3 filters, 4 filters, 5 filters, 6filters, 7 filters, 8 filters, or more filters. Some or all of theplurality of acoustic wave filters can be acoustic wave filters.

The first filter 192 is an acoustic wave filter arranged to filter aradio frequency signal. The first filter 192 can include acoustic waveresonators coupled between a first radio frequency node RF1 and thecommon node. The first radio frequency node RF1 can be a transmit nodeor a receive node. The first filter 192 includes two types of acousticresonators in accordance with any suitable principles and advantagesdisclosed herein. The other filter(s) of the multiplexer 195 can includeone or more acoustic wave filters, one or more acoustic wave filtersthat include two types of acoustic resonators in accordance with anysuitable principles and advantages disclosed herein, one or more LCfilters, one or more hybrid acoustic wave LC filters, or any suitablecombination thereof.

The acoustic wave filters disclosed herein can be implemented in avariety of packaged modules. Some example packaged modules will now bedisclosed in which any suitable principles and advantages of theacoustic wave filters and/or acoustic wave resonators disclosed hereincan be implemented. The example packaged modules can include a packagethat encloses the illustrated circuit elements. A module that includes aradio frequency component can be referred to as a radio frequencymodule. The illustrated circuit elements can be disposed on a commonpackaging substrate. The packaging substrate can be a laminatesubstrate, for example. FIGS. 20 to 24 are schematic block diagrams ofillustrative packaged modules according to certain embodiments. Anysuitable combination of features of these packaged modules can beimplemented with each other. While duplexers are illustrated in theexample packaged modules of FIGS. 21, 22, and 24, any other suitablemultiplexer that includes a plurality of filters coupled to a commonnode and/or standalone filter can be implemented instead of one or moreduplexers. For example, a triplexer can be implemented in certainapplications. As another example, one or more filters of a packagedmodule can be arranged as a transmit filter or a receive filter that isnot included in a multiplexer.

FIG. 20 is a schematic diagram of a radio frequency module 200 thatincludes an acoustic wave component 202 according to an embodiment. Theillustrated radio frequency module 200 includes the acoustic wavecomponent 202 and other circuitry 203. The acoustic wave component 202can include one or more acoustic wave filters in accordance with anysuitable combination of features of the acoustic wave filters disclosedherein. The acoustic wave component 202 can include an acoustic wavefilter with series TCSAW resonators and shunt BAW resonators, forexample.

The acoustic wave component 202 shown in FIG. 20 includes one or moreacoustic wave filters 204 and terminals 205A and 205B. The one or moreacoustic wave filters 204 includes an acoustic wave filter implementedin accordance with any suitable principles and advantages disclosedherein. The terminals 205A and 204B can serve, for example, as an inputcontact and an output contact. Although two terminals are illustrated,any suitable number of terminals can be implemented for a particularapplication. The acoustic wave component 202 and the other circuitry 203are on a common packaging substrate 206 in FIG. 20. The packagesubstrate 206 can be a laminate substrate. The terminals 205A and 205Bcan be electrically connected to contacts 207A and 207B, respectively,on the packaging substrate 206 by way of electrical connectors 208A and208B, respectively. The electrical connectors 208A and 208B can be bumpsor wire bonds, for example.

The other circuitry 203 can include any suitable additional circuitry.For example, the other circuitry can include one or more radio frequencyamplifiers (e.g., one or more power amplifiers and/or one or more lownoise amplifiers), one or more radio frequency switches, one or moreadditional filters, one or more RF couplers, one or more delay lines,one or more phase shifters, the like, or any suitable combinationthereof. The other circuitry 203 can be electrically connected to theone or more acoustic wave filters 204. The radio frequency module 200can include one or more packaging structures to, for example, provideprotection and/or facilitate easier handling of the radio frequencymodule 200. Such a packaging structure can include an overmold structureformed over the packaging substrate 206. The overmold structure canencapsulate some or all of the components of the radio frequency module200.

FIG. 21 is a schematic block diagram of a module 210 that includesduplexers 211A to 211N and an antenna switch 212. One or more filters ofthe duplexers 211A to 211N can include an acoustic wave filter inaccordance with any suitable principles and advantages disclosed herein.Any suitable number of duplexers 211A to 211N can be implemented. Theantenna switch 212 can have a number of throws corresponding to thenumber of duplexers 211A to 211N. The antenna switch 212 can include oneor more additional throws coupled to one or more filters external to themodule 210 and/or coupled to other circuitry. The antenna switch 212 canelectrically couple a selected duplexer to an antenna port of the module210.

FIG. 22 is a schematic block diagram of a module 220 that includes apower amplifier 222, a radio frequency switch 224, and duplexers 211A to211N according to an embodiment. The power amplifier 222 can amplify aradio frequency signal. The radio frequency switch 224 can be amulti-throw radio frequency switch. The radio frequency switch 224 canelectrically couple an output of the power amplifier 222 to a selectedtransmit filter of the duplexers 211A to 211N. One or more filters ofthe duplexers 211A to 211N can be an acoustic wave filter in accordancewith any suitable principles and advantages disclosed herein. Anysuitable number of duplexers 211A to 211N can be implemented.

FIG. 23 is a schematic block diagram of a module 230 that includesfilters 232A to 232N, a radio frequency switch 234, and a low noiseamplifier 236 according to an embodiment. One or more filters of thefilters 232A to 232N can include any suitable number of acoustic wavefilters in accordance with any suitable principles and advantagesdisclosed herein. Any suitable number of filters 232A to 232N can beimplemented. The illustrated filters 232A to 232N are receive filters.In some embodiments (not illustrated), one or more of the filters 232Ato 232N can be included in a multiplexer that also includes a transmitfilter. The radio frequency switch 234 can be a multi-throw radiofrequency switch. The radio frequency switch 234 can electrically couplean output of a selected filter of filters 232A to 232N to the low noiseamplifier 236. In some embodiments (not illustrated), a plurality of lownoise amplifiers can be implemented. The module 230 can includediversity receive features in certain applications.

FIG. 24 is a schematic diagram of a radio frequency module 240 thatincludes an acoustic wave filter according to an embodiment. Asillustrated, the radio frequency module 240 includes duplexers 211A to211N, a power amplifier 222, a select switch 224, and an antenna switch212. The radio frequency module 240 can include a package that enclosesthe illustrated elements. The illustrated elements can be disposed on acommon packaging substrate 247. The packaging substrate 247 can be alaminate substrate, for example. A radio frequency module that includesa power amplifier can be referred to as a power amplifier module. Aradio frequency module can include a subset of the elements illustratedin FIG. 24 and/or additional elements. The radio frequency module 240may include any one of the acoustic wave filters in accordance with anysuitable principles and advantages disclosed herein.

The duplexers 211A to 211N can each include two acoustic wave filterscoupled to a common node. For example, the two acoustic wave filters canbe a transmit filter and a receive filter. As illustrated, the transmitfilter and the receive filter can each be a band pass filter arranged tofilter a radio frequency signal. One or more of the transmit filters caninclude an acoustic wave filter in accordance with any suitableprinciples and advantages disclosed herein. Similarly, one or more ofthe receive filters can include an acoustic wave filter in accordancewith any suitable principles and advantages disclosed herein. AlthoughFIG. 24 illustrates duplexers, any suitable principles and advantagesdisclosed herein can be implemented in other multiplexers (e.g.,quadplexers, hexaplexers, octoplexers, etc.) and/or in switch-plexersand/or with standalone filters.

The power amplifier 222 can amplify a radio frequency signal. Theillustrated switch 224 is a multi-throw radio frequency switch. Theswitch 224 can electrically couple an output of the power amplifier 222to a selected transmit filter of the transmit filters of the duplexers211A to 211N. In some instances, the switch 224 can electrically connectthe output of the power amplifier 222 to more than one of the transmitfilters. The antenna switch 212 can selectively couple a signal from oneor more of the duplexers 211A to 211N to an antenna port ANT. Theduplexers 211A to 211N can be associated with different frequency bandsand/or different modes of operation (e.g., different power modes,different signaling modes, etc.).

The acoustic wave filters disclosed herein can be implemented in avariety of wireless communication devices. FIG. 25A is a schematicdiagram of a wireless communication 250 device that includes filters 253in a radio frequency front end 252 according to an embodiment. One ormore of the filters 253 can be acoustic wave filter in accordance withany suitable principles and advantages disclosed herein. The wirelesscommunication device 250 can be any suitable wireless communicationdevice. For instance, a wireless communication device 250 can be amobile phone, such as a smart phone. As illustrated, the wirelesscommunication device 250 includes an antenna 251, an RF front end 252, atransceiver 254, a processor 255, a memory 256, and a user interface257. The antenna 251 can transmit RF signals provided by the RF frontend 252. Such RF signals can include carrier aggregation signals. Theantenna 251 can receive RF signals and provide the received RF signalsto the RF front end 252 for processing. Such RF signals can includecarrier aggregation signals. The wireless communication device 250 caninclude two or more antennas in certain instances.

The RF front end 252 can include one or more power amplifiers, one ormore low noise amplifiers, one or more RF switches, one or more receivefilters, one or more transmit filters, one or more duplex filters, oneor more multiplexers, one or more frequency multiplexing circuits, thelike, or any suitable combination thereof. The RF front end 252 cantransmit and receive RF signals associated with any suitablecommunication standards. One or more of the filters 253 can include anacoustic wave filter with two types of acoustic resonators that includesany suitable combination of features of the embodiments disclosed above.

The transceiver 254 can provide RF signals to the RF front end 252 foramplification and/or other processing. The transceiver 254 can alsoprocess an RF signal provided by a low noise amplifier of the RF frontend 252. The transceiver 254 is in communication with the processor 255.The processor 255 can be a baseband processor. The processor 255 canprovide any suitable base band processing functions for the wirelesscommunication device 250. The memory 256 can be accessed by theprocessor 255. The memory 256 can store any suitable data for thewireless communication device 250. The user interface 257 can be anysuitable user interface, such as a display with touch screencapabilities.

FIG. 25B is a schematic diagram of a wireless communication device 260that includes filters 253 in a radio frequency front end 252 and secondfilters 263 in a diversity receive module 262. The wirelesscommunication device 260 is like the wireless communication device 250of FIG. 25A, except that the wireless communication device 260 alsoincludes diversity receive features. As illustrated in FIG. 25B, thewireless communication device 260 includes a diversity antenna 261, adiversity module 262 configured to process signals received by thediversity antenna 261 and including filters 263, and a transceiver 254in communication with both the radio frequency front end 252 and thediversity receive module 262. One or more of the second filters 263 caninclude an acoustic wave filter in accordance with any suitableprinciples and advantages disclosed herein.

Any of the embodiments described above can be implemented in associationwith mobile devices such as cellular handsets. The principles andadvantages of the embodiments can be used for any systems or apparatus,such as any uplink wireless communication device, that could benefitfrom any of the embodiments described herein. The teachings herein areapplicable to a variety of systems. Although this disclosure includesexample embodiments, the teachings described herein can be applied to avariety of structures. Any of the principles and advantages discussedherein can be implemented in association with RF circuits configured toprocess signals having a frequency in a range from about 30 kHz to 300GHz, such as in a frequency range from about 400 MHz to 8.5 GHz.

An acoustic wave filter including any suitable combination of featuresdisclosed herein be arranged to filter a radio frequency signal in a 5GNR operating band within Frequency Range 1 (FR1). A filter arranged tofilter a radio frequency signal in a 5G NR operating band can includetwo types of acoustic resonators in accordance with any principles andadvantages disclosed herein. FR1 can be from 410 MHz to 7.125 GHz, forexample, as specified in a current 5G NR specification. In 5Gapplications, an acoustic wave filter with a relatively wide pass bandand relatively low insertion loss can be advantageous for implementingdual connectivity. An acoustic wave filter in accordance with anysuitable principles and advantages disclosed herein can be arranged tofilter a radio frequency signal in a 4G LTE operating band and/or in afilter having a passband that includes a 4G LTE operating band and a 5GNR operating band. Filters disclosed herein can filter radio frequencysignals in a frequency range from about 400 MHz to 3 GHz in certainapplications.

Aspects of this disclosure can be implemented in various electronicdevices. Examples of the electronic devices can include, but are notlimited to, consumer electronic products, parts of the consumerelectronic products such as packaged radio frequency modules, radiofrequency filter die, uplink wireless communication devices, wirelesscommunication infrastructure, electronic test equipment, etc. Examplesof the electronic devices can include, but are not limited to, a mobilephone such as a smart phone, a wearable computing device such as a smartwatch or an ear piece, a telephone, a television, a computer monitor, acomputer, a modem, a hand-held computer, a laptop computer, a tabletcomputer, a microwave, a refrigerator, a vehicular electronics systemsuch as an automotive electronics system, a robot such as an industrialrobot, an Internet of things device, a stereo system, a digital musicplayer, a radio, a camera such as a digital camera, a portable memorychip, a home appliance such as a washer or a dryer, a peripheral device,a wrist watch, a clock, etc. Further, the electronic devices can includeunfinished products.

Unless the context indicates otherwise, throughout the description andthe claims, the words “comprise,” “comprising,” “include,” “including”and the like are to generally be construed in an inclusive sense, asopposed to an exclusive or exhaustive sense; that is to say, in thesense of “including, but not limited to.” Conditional language usedherein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,”“for example,” “such as” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orstates. The word “coupled”, as generally used herein, refers to two ormore elements that may be either directly coupled, or coupled by way ofone or more intermediate elements. Likewise, the word “connected”, asgenerally used herein, refers to two or more elements that may be eitherdirectly connected, or connected by way of one or more intermediateelements. Additionally, the words “herein,” “above,” “below,” and wordsof similar import, when used in this application, shall refer to thisapplication as a whole and not to any particular portions of thisapplication. Where the context permits, words in the above DetailedDescription using the singular or plural number may also include theplural or singular number respectively.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel resonators, filters,multiplexer, devices, modules, wireless communication devices,apparatus, methods, and systems described herein may be embodied in avariety of other forms. Furthermore, various omissions, substitutionsand changes in the form of the resonators, filters, multiplexer,devices, modules, wireless communication devices, apparatus, methods,and systems described herein may be made without departing from thespirit of the disclosure. For example, while blocks are presented in agiven arrangement, alternative embodiments may perform similarfunctionalities with different components and/or circuit topologies, andsome blocks may be deleted, moved, added, subdivided, combined, and/ormodified. Each of these blocks may be implemented in a variety ofdifferent ways. Any suitable combination of the elements and/or acts ofthe various embodiments described above can be combined to providefurther embodiments. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the disclosure.

What is claimed is:
 1. An acoustic wave filter comprising: a pluralityof series resonators including temperature compensated surface acousticwave resonators; and a plurality of shunt resonators including bulkacoustic wave resonators, the plurality of series resonators and theplurality of shunt resonators together arranged to filter a radiofrequency signal, and the acoustic wave filter being a band pass filter.2. The acoustic wave filter of claim 1 wherein the plurality of seriesresonators and the plurality of shunt resonators are co-packaged.
 3. Theacoustic wave filter of claim 2 wherein the plurality of seriesresonators is on a first die and the plurality of shunt resonators is ona second die, the second die being stacked with and attached to thefirst die.
 4. The acoustic wave filter of claim 3 wherein thetemperature compensated surface acoustic wave resonators includerespective interdigital transducer electrodes on a side of the first diethat is facing a side of the second die on which electrodes ofrespective bulk acoustic wave resonators are located.
 5. The acousticwave filter of claim 2 further comprising an inductor that isco-packaged with the plurality of series resonators and the plurality ofshunt resonators.
 6. The acoustic wave filter of claim 2 furthercomprising a trap circuit that is co-packaged with the series resonatorsand the shunt resonators.
 7. The acoustic wave filter of claim 2 furthercomprising a phase shift circuit that is co-packaged with the pluralityof series resonators and the plurality of shunt resonators, the phaseshift circuit including a plurality of interdigital transducerelectrodes.
 8. The acoustic wave filter of claim 1 wherein the pluralityof series resonators includes a Lamb wave resonator.
 9. The acousticwave filter of claim 1 wherein the plurality of shunt resonatorsincludes a Lamb wave resonator.
 10. The acoustic wave filter of claim 1further comprising a multi-mode surface acoustic wave filter coupled inseries with the plurality of series resonators.
 11. The acoustic wavefilter of claim 1 wherein the plurality of series resonators include aseries bulk acoustic wave resonator, and the temperature compensatedsurface acoustic wave resonators are coupled to an input/output port ofthe acoustic wave filter by way of the series bulk acoustic waveresonator.
 12. The acoustic wave filter of claim 1 wherein the acousticwave filter has a pass band that spans an operating band of a firstradio access technology and an operating band of a second radio accesstechnology, the first radio access technology being different than thesecond radio access technology.
 13. The acoustic wave filter of claim 1wherein the acoustic wave filter has a pass band that spans a Long TermEvolution operating band and a New Radio operating band.
 14. An acousticwave filter comprising: a plurality of series acoustic wave resonatorsof a first type; and a plurality of shunt acoustic wave resonators of asecond type, the series acoustic wave resonators of the first typehaving a higher quality factor below respective resonant frequenciesthan series acoustic resonators of the second type, the shunt acousticresonators of the second type having a higher quality factor in afrequency range between respective resonant frequencies and respectiveanti-resonant frequencies than shunt acoustic resonators of the firsttype, and the plurality of series acoustic wave resonators of the firsttype and the plurality of shunt acoustic wave resonators of the secondtype together arranged as a band pass filter configured to filter aradio frequency signal.
 15. The acoustic wave filter of claim 14 whereinthe plurality of series acoustic resonators of the first type aretemperature compensated surface acoustic wave resonators, and theplurality of shunt acoustic resonators of the second type are bulkacoustic wave resonators.
 16. The acoustic wave filter of claim 14wherein the plurality of series resonators of the first type are on afirst die and the plurality of shunt resonators of the second type areon a second die, and electrodes the plurality of series resonators ofthe first type are on a side of the first die that is facing a side ofthe second die on which electrodes of the plurality of shunt resonatorsof the second type are located.
 17. The acoustic wave filter of claim 14wherein the acoustic wave filter is a receive filter with a pass bandthat spans a first operating band and a second operating band, the firstoperating band being associated with a different radio access technologythan the second operating band.
 18. A wireless communication devicecomprising: an acoustic wave filter including a plurality of seriestemperature compensated surface acoustic wave resonators and a pluralityof shunt bulk acoustic wave resonators, the acoustic wave filter being aband pass filter; an antenna operatively coupled to the acoustic wavefilter; a radio frequency amplifier operatively coupled to the acousticwave filter and configured to amplify a radio frequency signal; and atransceiver in communication with the radio frequency amplifier.
 19. Thewireless communication device of claim 18 further comprising a basebandprocessor in communication with the transceiver.
 20. The wirelesscommunication device of claim 18 wherein the wireless communicationdevice is configured to support dual connectivity, the radio frequencyamplifier is a low noise amplifier, the acoustic wave filter is areceive filter having a passband that spans a first operating band and asecond operating band, and the first operating band is associated with adifferent radio access technology than the second operating band.